Pneumoneedles are well known for use in medical procedures such as insufflation of the abdomen. Such a needle generally comprises a housing having manually engageable surfaces and proximal and distal ends; a stopcock valve located generally adjacent the proximal end of the housing; a needle having an elongate tubular body or lumen, and proximal and distal ends; and an elongate stylet situated generally within the needle lumen and having proximal and distal ends. The distal end of the stylet is blunt to restrict damage to tissue such as internal organs; and the distal end of the needle is sharp to pierce tissue.
The stylet is mounted to afford reciprocating longitudinal movement relative to the needle between a protecting position with the distal end of the stylet extending beyond the distal end of the needle and a retracted position with the distal end of the stylet retracted to expose portions of the sharp distal end of the needle to afford puncture of tissue (e.g. the abdominal wall) by the needle. A spring is present to bias the stylet toward the protecting position.
Prior art Veress-needles are disclosed in U.S. Pat. No. 4,808,168 to Warring. This and other Veress-needles of the prior art suffer many drawbacks. First, the stylets of the prior art pneumoneedles are merely biased toward a protecting position and cannot be positively retained in the protecting position. This is particularly important once the needle enters the abdominal cavity where it is near sensitive tissue and organs. If the prior art Veress-needles are pressed against sensitive tissue or an organ, there is a potential that the styler may deflect, thereby exposing the sharpened end of the needle with the attendant risk of undesirable tissue/organ damage from the sharp needle.
Another drawback of prior art Veress-needles is that the location of the stopcock valve is not desirable for some types of procedures. In one procedure, for example, after the pneumoneedle has apparently pierced the peritoneum, a saline/vacuum test would be conducted to determine whether the needle has actually entered the abdominal cavity. The saline/vacuum test comprises filling the barrel portion of the stopcock valve with saline solution (e.g. with a syringe) and then manually grasping the abdomen and lifting to expand the abdominal cavity. If the Veress-needle has entered the abdominal cavity, such action will create a vacuum and cause the saline solution to flow through the Veress-needle thereby indicating that the Veress-needle has entered the abdominal cavity.
Prior art Veress-needles such as those described in U.S. Pat. No. 4,808,168 encounter difficulties during such a test. For example, if such a Veress-needle is placed in a generally horizontal position, then the saline solution tends to spill, thereby rendering the saline/vacuum test useless and wasting valuable operating room time.
Another problem associated with prior art Veress-needles also arises out of the position of the stopcock relative to the housing. For example, the Veress-needles shown in U.S. Pat. No. 4,808,168 have a stopcock valve located generally adjacent a proximal end of the housing. The barrel portion of the stopcock is disposed generally coaxially with the longitudinal axis of the Veress-needle. Such a location is believed to provide an inconvenient position for connection to the tubing used for passage of the insufflating gas.